Mechanical duster



April-12, 1938. l.. D. GocDHUE 2,114,092

i MCHANICAL DUSTER Filedl March 9, 1937 l 2 Sheets-.Sheet l gmc/rm EE E L D Eunn1-1UE flume April l2,` 1938. y l.. D. GooDHUE 2,114,092 I v MEQHANICAL DUSTER Filed March 9, J937 2 Sheets-Sheet 2 gnam L DE UUDHUE Patented Apr. 12, 1938/ [UNITED STATES MECHANICAL DUS'TEB.

Lyle D. Goodhue, Berwyn,

Md.; dedicated to the free use of the People of the United States Application March 9,

1 Claim.

amended April 30,

This applicationlis made under the act of March 3, 1883, as amended by the act of, April 30, 1928, and the invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

I hereby dedicate the invention herein de- V'scribed to the free use of the People of the United States to take effect on the granting of a patent to me.

My invention relates to a new and useful mechanical duster and more particularly to a duster which can be used to disperse finely divided insecticidal materials in the air which after settling on the foliage of plants is intended to give protection against the ravages of. insects.

The object of my invention is to-provide a mechanical duster that will give a very fine dispersion cf almost smoke-like appearance which will penetrate dense foliage and cause a deposit to be formed on the under side of the leaves as well as on the upper side.

Another object of my invention is to proj' vide a mechanical duster that will disintegrate lumps or aggregates that are held together more or less rmly by the cohesion or adhesion of a number of individual particles.

And still another object of my invention is to provide a means of retaining these dust aggregates,' lumps `or larger particles and returning them to the blower of the machine a number of times until they are suiiiciently disintegrated to be expelled in a very finely divided form.

Numerous types of. mechanical dusters have been known and used for a long time. My duster is of the continuous type which employs a blower to produce -a current of air which serves as a carrier for the material being dusted. However, to the best of my knowledge, no device has been used to separate the large particles and aggregates after they have once passed the blower and return them to the inlet where they will again be carried through and again be subjected to the grinding action of a high speed rotary blower.

My invention centrifugally separates the large particles from the fine particles and returns them to the blower until they are sufficiently disintegrated to be expelled.

The'device which accomplishes this separation consists of a curved tube eiitending from the outlet of the blower to the infet. A junction of a smaller tube is formed near the outlet of the blower on the inside of the curve of the large 1937, Serial No. 129,806

Granted under the act of March 3, 1883, as

tube. An opening is provided in the large tube near the inlet of the blower for the purpose of receiving the dust as it is fedinto the machine'. 'I The larger and heavier particles follow the longer wall of the large curved tube by virtue of the momentum imparted to them by the blower and induced air currents. The outlet tube', being'l joined to the shorter wall, is in such a position as to receive only the ilner particles of dust which are expelled by the portionv of the air stream escilng through this outlet tube.

My invention can be more specifically described by referring to the somewhat diagrams maticalsdrawings in which Figure 1 is a side elevation, Figure 2 a front elevation, and Figure 3 a top plan view.

Similar numerals referfto similar parts throughout the several views. ,g A high speed blower having properly designed rotating blades has an outlet connected to a curved tube I, which is again attached and forms a part of the inlet 2 to the blower. An outlet tube 3 of smaller diameter forms a junction with the large outlet 4 of the blower which is near the entrance to fthe circulating tub I and on its wall nearest the center of the circle which it describes in passing from. the outlet 3 to the inlet 2 of the blowen The opening 5 near the inlet 2 of the blower is an orifice for the reception of the dust being fed into the machine. Thehousing 6, encloses a rotor (not shown) with properly designed blades (not shown), which is a common essential part of any blower, whether it is used for the dusting of insecticides or for other purposes. A mechanisml to feed the dust into the machine is already known and is, therefore,.not shown. Likewise, the source of power is not described for the same reason.

By varying the ratio of the diameter of the' outlet tube 3 to the circulating tube I any desired separation of the large andsmall par- ,ti'cles'c'an be obtained, provided that the angle at which the vtube 3 meets the tube I is near 90 degrees, and'that the diameter of the circulating tube I is smaller than that of the main outlet of the blower. Also by varying the radius of curvature of. the circulating tube I-at the junction with the outlet tube 3, the degree of centrifugal separation can be varied. A variation of the speed of the blower will also alter the degree of separation..

A The operation of my large particles are centrifugally separated from duster in which the the small ones and returned again and again.

to the blower may be explained as follows:

During the operation, the blower is run at a speed varying from 5,000 to 15,000 revolutions 5 per minute, depending on the size of the machine, causing a current of air to/be forced at a high speed` through the circulating vtube I and at :the same time a smaller current o1 air to be /expelled through the outlet tube 3, which Y 10 causes an equal amount of air to be drawn in the" orifice 5. Insecticidal dust isA fed to the orifice 5 by a suitable mechanism (not shown) ilrom where it is drawn into the blower by the' /current of air circulating in the tube I, agitated 175'/ violently and expelled into tube I and tube '3.'

The large particles are thrown against the larger circumference of tube i by their momentum while the liner particles, which according to Stokes law require a much greater force to;cause 20 them to settle at the same rate as"the"lrge particles, remainv suspended and are in part expelled through the `outlet tube l. The large particles are again returned to the blower by way ofthe circulating tube I where they arel 25 mixed with the incoming dust. The large par'- ticles are thus returned again and again until they are disintegrated and expelled through the outlet tube 3.

My duster is especially adapted -for dusting greenhouses, mushroom houses or other enclosed cidal materials, a blower housing having a curved,

connecting tube from the outlet tothe inlet thereof; a. smaller outlet tube adapted to be joined to the wall of the connecting tube nearest the center of the curve described by said connecting tube and near the main outlet of the housing; and an oriiice in the connecting tube near the inlet of the housing for the reception of dust.

LYLE D. GOODHUE. 

